Seismic surveying is used for identifying subterranean elements of interest, such as hydrocarbon reservoirs, freshwater aquifers, gas injection zones, and/or the like. In seismic surveying, seismic sources are activated to generate seismic waves directed into a subterranean structure.
The seismic waves generated by a seismic source travel into the subterranean structure, with a portion of the generated seismic waves reflected back to the surface where the reflected waves are received by seismic sensors (e.g. geophones, accelerometers and/or the like). The seismic sensors produce signals that represent detected seismic waves. Signals from the seismic sensors are processed to yield information about the content and characteristics and/or images of the subterranean structure.
A land-based seismic survey arrangement may include a deployment of an array of seismic sensors at a land-air interface, in a borehole and/or the like. A marine survey arrangement may include placing a seabed cable or other arrangement of seismic sensors on the seafloor.
The seismic waves can be recorded with various types of seismic sensors (geophones, accelerometers, MEMS, rotational sensors, gradient sensors, divergence sensors, hydrophones). The term “sensor” as used herein is intended to cover all devices that are used to detect signals transmitted through the ground in methods of seismic exploration. The “Sensor” therefore includes multi-component sensors that may comprise a plurality of hydrophones, geophones, accelerometers and/or the like.
Different sensors are sensitive to different parts of the seismic wavefield. The data can be locally stored (nodal based system) or sent to a recording station (cable based system). This data is then processed to obtain sub-surface information. High fidelity measurement is required to provide accurate information.
Land operations can include measuring the seismic wavefield on-shore, by deploying at least some of the seismic sensors at or just below the surface. As such, for effective seismic-land-surveys, the sensors need to be effectively coupled with the land/soil/earth formation to provide for the sensors receiving/recording reliable/accurate seismic data. Various embodiments described herein address various issues related thereto.
From herein, the terms “land” and “soil” may refer to a variety of materials in which (or on which) the sensors are deployed in a land-based seismic survey. “Land” or “Soil” therefore includes any type of surface condition, e.g. dirt, sand, hardpan, rock, concrete, mud, submerged sediments and/or the like.